Coolant pumps generally serve to convey a liquid cooling medium for the purpose of cooling an internal combustion engine, electronics, an accumulator, an intercooler, a turbo charger etc. The pump module is driven by the electric drive motor. The electric drive motor has a split case or a separating can that separates a wet chamber, holding the liquid coolant, from a dry chamber. A permanently excited motor rotor rotates in the wet chamber, which rotor is arranged on a rotor shaft. The wet chamber is separated by the separating can/split case from a dry chamber containing the electronically commutated motor stator. The motor stator is formed by a plurality of stator coils. A Hall sensor is provided in the dry chamber at the separating can to detect the rotary position of the motor rotor for the purpose of electronic commutation, the sensor being spaced from the motor rotor.
A very precise and reproducible positioning of the Hall sensor is essential for a high control quality since even small deviations in the Hall sensor position with respect to its desired position, as well as vibratory movements of the Hall sensor during operation may adversely affect electronic commutation.
CN 19 41 569 describes a canned pump which comprises a sensor receptacle on which magnetic field sensors are arranged to detect the position of the motor rotor. The sensor receptacle opening is here oriented parallel with the rotating shaft of the rotor.
JP 2001 30 41 80 describes a canned pump with four induction sensors for detecting the motor rotor position. The sensors are arranged in the region of the separating can.